Friction clutch



L. B. GREEN FRICTION CLUTCH Nov. 1l, 1930.

original Filed March 25. 1927 INVENTO R ATTO RN EYS Qwwww Patented Nov.11, 1930 UNITED STATESl PATENT once LEE IB. GREEN, OF LAKEWOOD, OHIO,ASSIGNOR TO THE BORDEN COMPANY, OF WARREN,

' OHIO, A. CORPORATION 0F OHIO raic'roiv CLUTCH riginal application ledMarch 2 5, 1927, Serial No. 178,242, now Patent No. 1,772,863, datedAugust 12, 1930. Divided and this application led July 12, 1928. SerialNo. 292,103.

This invention relates to a friction clutch mechanism.

The clutch mechanism constructed in accordance with the invention willbe herein illustrated and described in connection with a centrifugaldrier such as is disclosed in my copending application Serial No.178,242, patented August 12, 1930; No. 1,7 72,863, and of which thisapplication is a division. It should be understood, however, that theclutch mechanism of the present invention is not limited in its use to acentrifugal drier but issusceptible of being used in variousrelationships and in various devices wherever it is desirable to connecta driving member with a driven member.

An object of the present invention is to provide a clutch mechanismwhich will permit of slippage between the driving member and drivenmember during starting of the device with which it is used, or uponoverloading of the driven member so that the driving means or motor forthe driving member will not be overloaded at such times.

Another object is to provide a clutch mechanism capable of withstandingWear.

Another object is to provide a clutch mechanism which is readilyadjustable to compensate for wear. v

Another Objectis to provide a clutch mechanism capable of accomplishingthe foregoing objects which is of simple and economical construction. i

Additional objects and advantages will become apparent as thedescription of the invention proceeds.

An embodiment of the invention is illustrated in the accompanyingdrawing wherein f Fig. 1 is a vertical sectional view of a centrifugallclothes drier, the clutch mechanism being shown as coupling the drivingand driven portions of the drier; and

Fig. 2 is a fragmentary detail view showing the clutch mechanism on alarger scale than in Fig. 1. i

Although a clutch mechanism according to the present invention isadaptable for use with various forms of devices wherein there aredriving and driven members, it is herein shown and described as beingemployed in a centrifugal clothes drier, such illustration anddescription, however, being purely by way of example and intended merelyto set forth one particular application and use of the invention.

Referring particularly t`o Figs. 1 and 2, the casing of the machine,which may be generally cylindrical, has a side wall 10 of sheet metalwith a bottom 11 of the same material provided with a central opening.The bottom of the casing may have suitable reinforcements sucli as aperipheral element 12 and a ring 13 surrounding the opening in thebottom of the casing. The ring 13 has secured thereto by a plurality ofmachine screws 14 a bearing supporting casting 15. The casting 15 isinternally shouldered to support the outer race 16 of a radial andthrust .ball bearing, the outer race being held to the shoulder by aring 17, which is secured to the casting by screws 18. The inner race ofthis bearing abuts against an enlargement 20 on a shaft' 21, being heldin position by a washer and nut 22 and 23, respectively, the nut beingthreaded on the shaft 21. Packing rings 24 are mounted on the lower partofthe casting 15 to prevent the escape of lubricating oil. rl`he shaft21 extends downwardly out of the casting 15 and at its lower end hasprovision for connection with some driving means which, in the drawings,takes the form of a flexible shaft 25 having a driving pin 25 working ina slot 26 in the shaft 21. Next above the enlargement 20 of the shaft 21is a washer 29 which supports the lower end of a spiral spring 30 formedof wire of square cross-section which is ground to an accuratemeasurement on its outersurface and constitutes the inner race of aroller clutch, two of the rollers of which are shown at 31. The rollers3l are mounted in a cage, the upper and lower portions of which areshown at 32 and 33 respectively. Above the spring 30 is a second washer34 which may be caused to compress the spring 30, a nut 35 with a lockwasher 36 being employed for this purpose, the nut 35 being threadedupon the reduced upper end of the shaft 21. /By increasingj/:heVcompression of the spring 30 its diameter may ICO d clothes container oftwo parts, one of which An annular sheet metal element 44 has abeincreasedwhereby the friction in the roller clutch is varied andcontrolled. The outer race 56 of the roller clutch is extended up-Wardly to form an enclosure for the nut 35 and its upper end hasattached thereto by screws 3f?, or the like, a-casting 38 which iscentrally bored to receive a bushing 39 fitting the shaft v21 andcounterbored to receive a steel bearing disk 40 and a steel ball 41,these latter parts transmitting end thrusttothe shaft 21, the rollers 31taking radial thrust only. The upper end of the casting 38 yis taperedslightly to receive with a tight sliding fit a tapered sleeve 42 uponwhich is mounted an annular block 43 of soft rubber;

viange 45 at the bottom thereof which is welded or otherwise secilred tothe bottom 11 of the machine casing, while at its upper end the element44 carries a packing ring 46 thus enclosing the rotating parts andpreventing the discharge of lubricating oil.

From the description thus far set forth it should be observed thatconsidering the invention in its broad aspects the shaft 21 representsthe driving'member While the casting 38 and the outer race 56 representthe driven member, the`coil spring and the rollers 31 forming a frictionclutch or coupling between such driving and driven members.-I Of coursethe driven or rotating portions of the centrifugaldrier disclosed in thepresent embodiment also form, in this specic instance,

' a part of the driven member. These portions may be briefly describedas comprising a is an outer vessel47 having a central uplstanding andpreferably conoidal portion 48 provided with a bead 49 in its walladapted,

'toabut against'the lower end of theblock 43 and having a series ofsmall rounded projections 50 that take into the rubberof the block' 43lso that afgood driving connection results.

',lhe closed upper end of the upstanding portiony 48 may rest upon theupperen'd of the block 43. The other part of the container vis aperforated disk 51 also preferably provided withv a central upstandingportion 52 of -conoidal form which rests upon the upstanding` portion 48of the outer vessel and has-a frictional engagement therewith s o thatrotation .imparted` tof; the outer vessel 47 is transmttedtothebasket5"1;\;

It is not thought to be`nec`essary v scribe or s'p'ecically -set forth`further details of the centrifugal drier since sufficient have alreadybeenfexiumerated to fullyexplainjthe operation ofthe clutchmechanism/and lits relation to the particular device with which it isused in the present embodiment.- The j further details of thecentrifugal drier and repeated. s

the advantages resulting therefrom are fully l set forth in myco-p'en'ding application above mentioned and, therefore, will not now beIn operation, the spring 30 is adjusted by expansion and contraction ofits diameter through an' adjustment of the compression exerted thereonby the washer 36 and nut 35. It will be observed that the .coils lof thespring stand at an angle to thehorizontal, that is assuming that theshaft 21 is a vertical shaft. When the spring is compressed, theangularity of these coils 1s lessened, that is they are vbrought towardthe horizontal, tiltedupon horizontal axes, as it were.

vHence, while their diameters may not necesv -sarily be increased,`these diameters are brought more nearly into perpendicular relationwiththe rollers 31, and the springs are thereby forced outwlardlyagainst those rollers. action .is aminute one only, as the rollers andthe outer surfaces of the spring are accurately finished and anextremely small ad? It should be understood that this I rotates with it,being clamped between the collar 20 and nut 35'. The outer race 56 ofthe roller bearing, and the parts secured thereto, possess considerableinertia. This inertia at the start is of greater effect than thefriction in the roller bearing., Hence the rollers 31 are rotated by thespring 30 and caused to roll upon therace 56. At the same time, however,the friction between the rollers 31 and the race 56 tends. to produce'rotation inthe latter, and this tendency gradually builds up until therace 56v with its associated parts begins to rotate. Friction actingthereafter in the same manner gradually increases the speed of rotationof the driven parts untilt may nearly, if not .n

quite, equal the speed ofthe shaft 21, atl which time, vof course,the'rollers 31- have no .rotation upon their own axes. In'the same wayshould anioverload b e placed upon the driven member av slippagewillimmediately take lace in the clutch mechanism, thereby allowlng thedriving'member to 'rotate or be operated'without'an overloadingv of thef-fsource of powerpr driving motor.' f

The adjustment featurealready set forth),l I l, permits the clutch andthe degree ofslipage Ito be accurately adjusted in accor ance with vtheconditions to whichfthe mechanism is to be subjectedA and also totalseup whatever wear mightvoccur between the v parts of, the.clutchfmechanism.l However, this last feature of adjustment'willprobablynever be necessary or, if necessary, only at rare intervals since everyelement of the clutch mechanism is a metallic member and, therefore, notreadily subject to Wear.

Although a preferred embodiment of the invention has been illustratedand described herein it should be understood that the same 'I is not tobe limited thereto but is susceptible of various modifications andadaptations falling Within the scope of the appended claims.

Having thus described my invention, I

claim i regulating the amount of Afriction in said 1.V In a clutchmechanism, a driving member, a driven member and a couplingtherebetween, said coupling comprising a roller bearing, a spiral springassociated With one of said members and forming one of the races forsaid bearing, means associated-With c the other of said members andforming the `other race for said bearing, and means for compressing saids ring endwise to a greater or lesser extent or va'lrying the efectivediameter of the race of the bearing formed thereby and thus regulatingthe amount of friction uinv said bearing. x

2. In a clutch mechanism, a driving member, a drivenmelnber and acoupling therebetween, said coupling comprising a roller bearing, aspiral spring associated With the driving member and forming the innerrace of the bearing, means associated with the driven member and'forming the outer race of the bearing, andmeans for compressmgsaidspring endwise to a greater or lesser extent for varying theeffective diameter of the inner race of the bearing and thereby bearing.

3. In combination, a driving mechanism including a shaft, and alfriction clutch therefor comprising a roller bearing for the shaft, theinner race of said bearing a spiral spring, a shoulder on t e shaft iagainst which said springs bears atone end and a nut therefor on theshaft for applying pressure on the other end of said spring whereby theeffective diameter of the inner race may be varied.

In testimony whereof, I hereunto aix my signature. y

' f LEE B. GREEN.

having

